bvscalculator.py

#!/usr/bin/env python
##############################################################################
#
# diffpy.srreal     by DANSE Diffraction group
#                   Simon J. L. Billinge
#                   (c) 2010 The Trustees of Columbia University
#                   in the City of New York.  All rights reserved.
#
# File coded by:    Pavol Juhas
#
# See AUTHORS.txt for a list of people who contributed.
# See LICENSE_DANSE.txt for license information.
#
##############################################################################
"""Class BVSCalculator -- bond valence sums calculator."""


# exported items
__all__ = ["BVSCalculator"]

from diffpy.srreal.srreal_ext import BVSCalculator
from diffpy.srreal.wraputils import (
    propertyFromExtDoubleAttr,
    setattrFromKeywordArguments,
)

# Property wrappers to C++ double attributes

BVSCalculator.valenceprecision = propertyFromExtDoubleAttr(
    "valenceprecision",
    """Cutoff value for valence contributions at long distances.
        [1e-5]""",
)

BVSCalculator.rmaxused = propertyFromExtDoubleAttr(
    "rmaxused",
    """Effective bound for bond lengths, where valence contributions
        become smaller than valenceprecission, read-only.  Always smaller or
        equal to rmax.  The value depends on ions present in the structure.
        """,
)

BVSCalculator.rmin = propertyFromExtDoubleAttr(
    "rmin",
    """Lower bound for the summed bond lengths.
        [0 A]""",
)

BVSCalculator.rmax = propertyFromExtDoubleAttr(
    "rmax",
    """Upper bound for the summed bond lengths.  The calculation is
        actually cut off much earlier when valence contributions get below
        valenceprecission.  See also rmaxused and valenceprecission.
        [1e6 A]""",
)


# method overrides that support keyword arguments


def _init_kwargs(self, **kwargs):
    """Create a new instance of BVSCalculator.
    Keyword arguments can be used to configure the calculator properties,
    for example:

    bvscalc = BVSCalculator(valenceprecision=0.001)

    Raise ValueError for invalid keyword argument.
    """
    BVSCalculator.__boostpython__init(self)
    setattrFromKeywordArguments(self, **kwargs)
    return


def _call_kwargs(self, structure=None, **kwargs):
    """Return bond valence sums at each atom site in the structure.

    Attributes
    ----------
    structure
        structure to be evaluated, an instance of diffpy Structure
        or pyobjcryst Crystal.  Reuse the last structure when None.
    kwargs
        optional parameter settings for this calculator

    Return an array of calculated valence sums.
    See valences for the expected values.
    """
    setattrFromKeywordArguments(self, **kwargs)
    rv = self.eval(structure)
    return rv


BVSCalculator.__boostpython__init = BVSCalculator.__init__
BVSCalculator.__init__ = _init_kwargs
BVSCalculator.__call__ = _call_kwargs

# End of file